AbstractField collections of over-wintering and summer adults and nymphs of Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), Lygus borealis (Kelton), and Lygus elisus Van Duzee were made weekly in five fields in Saskatchewan in 1998 and 1999. The crops sampled were alfalfa, Medicago sativa L. (Leguminosae), canola, Brassica napus L. (Cruciferae), and mustard, Sinapis alba L. (Cruciferae), at Vonda, and alfalfa and canola at Saskatoon. In alfalfa, the most abundant Lygus spp. found in May and June were over-wintering adult L. lineolaris and (or) L. borealis; the predominant species in mid-June to early July was L. borealis; and the population from mid-July to late August was dominated by L. lineolaris. In canola, adult populations of Lygus spp. were not found until mid-June. The predominant species, L. lineolaris, probably over-wintering adults, was first detected in canola at the early bud stage in late June to early July; high numbers of L. lineolaris adults occurred in canola in mid-August. Populations of Lygus spp. in organic mustard were negligible. Dissections of field-collected Lygus spp. nymphs revealed parasitism in up to 70% of the midsummer population in alfalfa. In contrast, less than 1% of the late-season Lygus spp. population, primarily L. lineolaris in canola and L. lineolaris and L. borealis in alfalfa, was parasitized.
摘要 1998 年和 1999 年,我们每周都在萨斯喀彻温省的五块田间采集 Lygus lineolaris (Palisot de Beauvois)(半翅目: Miridae)、Lygus borealis (Kelton) 和 Lygus elisus Van Duzee 的越冬和夏季成虫及若虫。取样的作物包括冯达的紫花苜蓿(豆科)、油菜(十字花科)和芥菜(十字花科),以及萨斯卡通的紫花苜蓿和油菜。在紫花苜蓿中,5 月和 6 月发现的最多的 Lygus spp.是越冬的 L. lineolaris 和(或)L. borealis 成虫;6 月中旬至 7 月初的主要物种是 L. borealis;7 月中旬至 8 月下旬的种群主要是 L. lineolaris。在油菜籽中,直到 6 月中旬才发现 Lygus spp.的成虫种群。6 月下旬至 7 月上旬,在油菜花的初芽阶段首次发现了主要物种 L. lineolaris,可能是越冬成虫;8 月中旬,油菜花中出现了大量 L. lineolaris 成虫。有机芥菜中的 Lygus 种群数量可以忽略不计。对田间采集的 Lygus spp.若虫进行解剖后发现,在紫花苜蓿的仲夏种群中,寄生率高达 70%。相比之下,晚季 Lygus spp.(主要是油菜中的 L. lineolaris 和紫花苜蓿中的 L. lineolaris 和 L. borealis)种群的寄生率不足 1%。